Since all these other people have used speed and rotations in their answer, I will offer an alternative. Instead of focusing on the rotations, you could look at the force and work used to go up the hill. By doing so, you can use the equation W = (F)(d)(cosine angle). Plus, if the force is perpendicular, the cosine of the angle is cancelled out, making it W = Fd.
At least, I think you can apply it that way. If not, just disregard the answer above.
